FUR SEALS AND OTHER LIFE, PRIBILOF ISLANDS, I914. 37 



Estimate of nonbreeding seals, 1914. 

 Yearlings: 



Pups bom in 1913 and actually counted 92, 269 



Deduction for natural mortality in first year, 50 per cent 46, 134 



Yearlings of both sexes in 1914 46, 135 



Two-year-olds: 



Pups bom in 1912 and actually counted 81, 984 



- Deduction for natural mortality in first year, 50 per cent 40, 992 



Yearlings in 1913 40, 992 



Deduction for nattu'al mortality in second year, 15 per cent 6, 148 



Two-year-olds of both sexes in 1914 34, 844 



Three-year-old males: 



Pups bom in 1911, on the basis of the estimated average harem on one rookery, 



Kitovi 47, 230 



Addition for probable error in method 23, 615 



Estimated number of pups born in 1911, by average harem method 70, 845 



Estimated number of pups born in 1911, by inference from number couated in 1912. 82,000 



Conservative mean between the results of the two methods 75, 000 



Deduction for first year's mortality, 50 per cent 37, 500 



Yearlings in 1912 37, 500 



Deduction for second year's mortality, 15 per cent 5, 625 



Two-year-olds of both sexes in 1913 31, 875 



Deduction for females, 50 per cent 15, 938 



Two-year-old males in 1913 iS, 937 



Two-year-old males killed in 1913 515 



Two-year-old males at close of 1913 15, 422 



Deduction for mortality in third year, 10 per cent i, 542 



Three-year-old males at beginning of 1914 13, 880 



Four-year-old males: 



Estimate of number bom in 1910, based on average harem of Kitovi 43, 777 



Addition for estimated error in method 21, 888 



Estimated pups bom in 1910 65, 665 



Deduction for assumed natural mortality in first year, 50 per cent 32, 833 



Yearlings, both sexes, in 191 1 32, 832 



Deduction for nattual mortality in second year, 15 per cent 4, 925 



Two-year-olds, both sexes, in 1912 27, 907 



Deduction for females, 50 per cent 13, 953 



Two-year-old males in 1912 13, 954 



Killed as two-year-olds in 1912 541 



Two-year-old males at close of 1912 13, 413 



Deduction for natural mortality in third year, 10 per cent i, 341 



Three-year-old males in 1913 12, 072 



Killed as three-year-olds in 1913 i, 610 



Three-year-olds at close of 1913 10, 462 



Deduction for mortality in fourth year, 5 per cent 523 



Four-year-old males in 1914 9, 939 



